The present invention relates to digger derrick trucks used for installing telephone poles.
Conventionally, digger derrick trucks have the capability of being used to maneuver telephone poles and to act as a crane. Digger derrick trucks include an auger for drilling a hole into which the telephone pole is placed. A boom is secured to the upper portion of the truck and has a pole guide assembly slidably mounted thereon for grasping and stabilizing the pole while it is being installed into the ground. The boom includes three telescoping boom sections which are extendable and retractable relative to one another. The pole guide assembly is attached to the end of the outermost boom section in an operative position. In this position the pole guide assembly may be used to grasp and maneuver the telephone pole. In addition to the pole guide assembly, a rope may be attached to a crane assembly secured to the end of the boom and wrapped around the pole to help stabilize the pole as it is being moved. The digger derrick may also be used solely as a crane by moving the pole guide assembly along the outermost boom section and attaching it in an inoperative position to the middle boom.
Conventionally, the pole guide assembly is secured to the boom sections by a single pin. The pin extends through aligning apertures in both the pole guide assembly and the boom section to lock the position of the pole guide assembly. In order to reposition such conventional pole guide assemblies, the boom must be lowered to the ground and the pin must be manually removed. The pole guide assembly is then moved into the operative or inoperative position and the apertures in the pole guide assembly and the boom section are aligned. The pin is thereafter manually replaced to secure the pole guide assembly in the selected position on the respective boom section.
A problem with this method of moving such pole guide assemblies between an operative and inoperative position is that it is laborious. The pole guide assembly is heavy and difficult to move. The apertures in the pole guide assembly and boom sections sometimes fail to line up properly making insertion of the pin in the misaligned apertures difficult. A hammer, or any other tool which is available, must be used to force the pin into the apertures. Further, in cold or in element weather, removing and replacing the pin is even more difficult due to difficult environmental conditions.
It is desired to provide a method and apparatus for easily moving the pole guide assembly of a digger derrick truck between an operative and inoperative position.
The present invention provides an improved method and apparatus for moving the pole guide assembly of a digger derrick truck between an operative and inoperative position.
Digger derrick trucks include a boom on which a pole guide assembly is slidably mounted. The pole guide assembly is provided with a latching mechanism including a latch arm and a release mechanism. The release mechanism is actuated when the boom sections are retracted and allows pivoting of the latch arm. The latch arm moves between a first and second position to releasably couple the pole guide assembly and the boom in an operative and inoperative position.
The present invention provides a digger derrick truck for installing poles into the ground. The digger derrick truck includes a boom mounted thereon and a pole guide assembly slidably mounted on the boom. The pole guide assembly is operatively associated with a latching mechanism which has a first position in which the latch mechanism releasably couples the pole guide assembly and the boom in an operative position. The latch mechanism also has a second position in which the latch mechanism releasably couples the pole guide assembly and the boom in an inoperative position.
The present invention provides a digger derrick truck for installing poles in the ground. The digger derrick truck includes a boom mounted thereon and a pole guide assembly slidably mounted on the boom. The pole guide assembly has an operative position and an inoperative position. A latching mechanism includes a release mechanism mounted on the frame of the pole guide assembly and a latch arm operatively associated with the release mechanism. The latch arm has a first position releasably coupling the pole guide assembly and the boom in the operative position and a second position releasably coupling the pole guide assembly and the boom in the inoperative position.
The present invention provides a method for moving a pole guide assembly of a digger derrick truck between an operative and an inoperative position. The first step includes mounting the pole guide assembly on a boom secured to the digger derrick truck. The boom has a plurality of telescoping boom sections. A latch mechanism having a latch arm is mounted on the pole guide assembly. The telescoping boom sections of the boom are retracted actuating a release mechanism which is operatively associated with the latch arm. The latch arm pivots to releasably couple the pole guide assembly and the boom. The telescoping boom sections are then extended.
An advantage of the present invention is that the latching mechanism allows the pole guide assembly mounted on the boom of the digger derrick truck to be moved between an operative and inoperative position without requiring manual labor.
A further advantage of the present invention is that the latching mechanism may not be prematurely released to inadvertently uncouple the pole guide assembly from the boom.